Ideas that added muscle to the empirebuilders

A generation ago Eric Stokes's The English Utilitarians and India brought together the realms of intellectual history and the history of 19th-century British imperial government. Anthony Pagden has performed a similar service by providing a lucid account of the manner in which European philosophers and statesmen conferred ideological legitimacy on the huge overseas empires built between the days of Hern n Cortes and Napoleon Bonaparte.

He shows how critics of imperial policies were also able to draw on biblical and classical precedents to challenge that legitimacy. Some of the themes he explores have been anticipated in the work of scholars such as John Pocock, John Elliot, David Armitage and Anthony Pagden himself, but the comparative scope of this book and its compelling analysis of contemporary writings make it essential reading for historians of empire and for European intellectual historians alike. The forward thrust of European empires was powered not only by capitalistic commercial forms and political rivalries between emerging nation states, but also by a powerfully developed western ideology which asserted the legitimate dominion of its kings and emperors over the world.

In the early chapters, Pagden shows how the Roman concept of dominium totius orbi fused with the Christian notion of unlimited spiritual expansion and was then projected outside Europe. This fundamental tradition was sometimes invoked even by the polite and commercial colonisers of the north European empires. Differences of emphasis developed, however, in the 17th and 18th centuries between and within national traditions.

The official Iberian ideology, invigorated by the counter-Reformation, adopted a hard version of Christian Roman imperial theory, stressing military glory and conversion. French and English thinkers, by contrast, often looked back to the Athenian Achaean League and tended to see an ideal empire as a free contract, based on culture and commerce, entered into between a mother state and its colonies. By the mid-18th century, the experience of costly colonial wars and the beginnings of large territorial empires gave yet greater prominence to the Greek as opposed to the Roman model.

Thinkers as various as Diderot, Condorcet, Montesquieu and Smith regarded territorial empires as costly abominations. Ill-gotten colonial wealth and the vicious exploitations of the slave trade which were the inevitable concomitants of territorial empire would serve only, they thought, to undermine civic virtue and private morality in Europe.

But this philosophical consensus was breaking down again by the end of the century. France under Napoleon was committed to a land empire within Europe; Britain to a territorial empire in Asia and, ultimately, Africa. The United States, the western arm of the old British empire, adhered to a Greek version of civic independence, but its dominion would still, for the forseeable future, be based on the expropriation of indigenous people and the exploitation of slave labour.

Theorists soon began to speak again of the European civilising mission, but it was one which was now shot through with Enlightenment and scientific justifications as much as the older emphasis on Roman legal precedent and evangelical necessity. Pagden's approach is that of classic intellectual history: a history of rational debate between western philosophers and lawyers over a world that is gradually becoming empirically known.

It would be interesting to know how his narrative would be revised if it were brought more closely together with the growing volume of work on European interactions with other peoples, represented for instance in Stuart B. Schwartz's recent edited volume Implicit Understandings. For here we encounter more of those other, face-to-face ideologies of empire - violent, visceral and often subversive of the grander constructions.

Pagden, for instance, records that Major-General Jeffrey Amherst, fighting in north America in the 1760s, was capable of accepting the broad legal doctrine that conquest should not deprive peoples of their rights. But this same Amherst had earlier stated that the American Indians were "the vilest race of beings that ever infested the earth" and had apparently condoned a plan of one of his field commanders to send smallpox-infested blankets among them in an early example of biological warfare.

Equally, when the legal and cultural objections to "miscegenation" between white and non white voiced by theorists broke down in practice, settlers were able to justify their practices by appropriating the theory of common human origins. Even as accomplished a history of influences and debates as this book raises questions about the working out of ideas in context and about those more fractious ideologies, prejudices, assumptions and judgements which manifested themselves and flourished in the interstices of colonial war and conquest.

C. A. Bayly is Vere Harmsworth professor of imperial and naval history, University of Cambridge.